Immediate grid with custom columns/rows

This example contains 2 custom column definitions: 1) to declare TypeId is an external key whose value is TypeName,
and whose values must be provided by an autocomplete. 2) to declare Price fas a colspan=2.
This examples handles also the possibility that some item models be a subclass containing futher properties.
For this reason a second row-type is defined whose type matches the subclass type, and whose column
definitions are inherited from the 0 index main row-type. Then, the new subclass specific MaintenanceYearlyRate column
is added and the Price colspan is overriden to 1 so that both fields fit into the Price column of the father class.
Column and row definitions may provide also custom edit/display templates defined in-line, with partial views and with ViewComponents.
Each control gives also the possibility to redefine its overall layout template. Thus, for instance, the grid control may be easily turned into
an ul/li list while keeping entirely its functionalities.
Please refer to this detail form example to see an in-line custom template definition.
Custom templates may be installed also globally by re-defining the partial
views with the default templates either in a controller specific folder or in the shared folder.